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01-15-2010, 03:05 PM   #46
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I'm using a friend's Windows 7 computer now with Firefox 3.5.7, and those 2 crayon pictures from page 2 look very different, just like they do on my home computers. Clearly, Firefox is not detecting an embedded color profile in Pentax camera-generated JPG files.

Further, in IE 8, there is NO color management enabled by default. The 3 pictures of strawberries posted by distudio look completely different, whereas they look the same in Firefox. I don't have access to IE at home, so I didn't have a chance to try it out until now. It's miserable, I'd hate to know that any pictures I post online look this bad to other people:



None of this is winning me to the dark side of Adobe RGB. I'm all for using techniques that maximize the quality of my pictures, but not at the risk of ending up with fugly colors.

01-15-2010, 04:14 PM   #47
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QuoteOriginally posted by GoremanX Quote
I'm using a friend's Windows 7 computer now with Firefox 3.5.7, and those 2 crayon pictures from page 2 look very different, just like they do on my home computers. Clearly, Firefox is not detecting an embedded color profile in Pentax camera-generated JPG files.
Maybe I led you up the garden path on this one? Following is a dump off my screen out of fully colour managed Firefox 3.5.7, they are different but not as much as I would expect an sRGB vs aRGB rendering of the same image should be.



QuoteOriginally posted by GoremanX Quote
Further, in IE 8, there is NO color management enabled by default. The 3 pictures of strawberries posted by distudio look completely different, whereas they look the same in Firefox. I don't have access to IE at home, so I didn't have a chance to try it out until now.
As far as I'm aware no versions of IE are colour managed at this point, I've no idea why, maybe it will eventually be available as a costly add on ;-)

QuoteOriginally posted by GoremanX Quote
None of this is winning me to the dark side of Adobe RGB. I'm all for using techniques that maximize the quality of my pictures, but not at the risk of ending up with fugly colors.
I think an AdobeRGB work-flow is quite workable so long as the user is aware of the steps that must be taken in order to make the files presentable for web or third party printing which generally translates to conversion to sRGB colour space.

On the personal print side of things shooting in AdobeRGB will generally end up producing better prints from a colour managed print application. Assuming of course that the user has at least gone to the trouble of obtaining and installing profiles for their preferred printer/paper combinations.

Shooting RAW provides the greatest flexibility as the colour space is not fixed but if this all appears too confusing/difficult/frustrating then sRGB is the easy way out. Simple really.
01-15-2010, 05:07 PM   #48
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I've just been through and deleted some off topic posts. This is the second time it has been necessary in this thread. Please don't make it necessary again.
If the two of you need to fight it out, please use the PM system so that other members involved in this thread aren't affected. Alternatively you might want to take advantage of the ignore member facility.
01-15-2010, 06:04 PM   #49
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QuoteOriginally posted by distudio Quote
Shooting RAW provides the greatest flexibility as the colour space is not fixed but if this all appears too confusing/difficult/frustrating then sRGB is the easy way out. Simple really.
Rob, I've always been of the understanding that the reason to go to as wide a gamut colourspace as is possible as early as is possible in the process is to try to ensure that there is minimal clipping of colour.

I may have alluded to that in an earlier post.
I recall about 10 years ago we were discussing this and you mentioned to convert RAW in the Prophoto coloursp[ace for this reason.

With this in mind, if you capture in sRGB right off the get go (I presume this would be jpeg capture, since only sRGB and aRGB are being bandied about), would you not be getting your clipping out of the way at the time of capture rather than risking some clipping down the road as part of either clumsy post processing or inevitable clipping when you convert to sRGB for screen or lab use?
As an aside, a Noritsu tech told me one time that wet process colour paper fits very nicely into the sRGB colour space, and that this was why Noritsu didn't bother with custom profiles.

01-15-2010, 06:05 PM   #50
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QuoteOriginally posted by Damn Brit Quote
I've just been through and deleted some off topic posts. This is the second time it has been necessary in this thread. Please don't make it necessary again.
If the two of you need to fight it out, please use the PM system so that other members involved in this thread aren't affected. Alternatively you might want to take advantage of the ignore member facility.
Done and done.
Thanks Gary.
01-15-2010, 06:23 PM   #51
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QuoteOriginally posted by Wheatfield Quote
Rob, I've always been of the understanding that the reason to go to as wide a gamut colourspace as is possible as early as is possible in the process is to try to ensure that there is minimal clipping of colour....

With this in mind, if you capture in sRGB right off the get go (I presume this would be jpeg capture, since only sRGB and aRGB are being bandied about), would you not be getting your clipping out of the way at the time of capture rather than risking some clipping down the road as part of either clumsy post processing or inevitable clipping when you convert to sRGB for screen or lab use?
By letting the camera manage the RAW conversion you are letting it determine how it clips/compresses the colours just like you are letting it clip highlights and shadow details.

Working in a wide gamut colour space or in effect working with RAW images using a wide gamut colour space simply allows the editor far more flexibility. Particularly in the case of desaturation or any other colour manipulation that will affect gamut plus it provides a choice of rendering intent and hence degree/type of clipping/compression that will be applied during conversion to a narrower gamut colour space.

QuoteOriginally posted by Wheatfield Quote
As an aside, a Noritsu tech told me one time that wet process colour paper fits very nicely into the sRGB colour space, and that this was why Noritsu didn't bother with custom profiles.
That may be the case, I will see if I can find a recent ICC profile for a wet process colour printer and poke it into this:

ICCView - Colormanagement, Helpdesk, OpenSource

Cheers,
01-15-2010, 07:59 PM   #52
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QuoteOriginally posted by distudio Quote
Maybe I led you up the garden path on this one? Following is a dump off my screen out of fully colour managed Firefox 3.5.7, they are different but not as much as I would expect an sRGB vs aRGB rendering of the same image should be.
See to my eye, that's a huge difference. Look specifically at the 5th crayon from the right, on the bottom row. In the top picture, it's clearly turquoise (aqua? sea green? foam green?). In the second picture, it's gone so pale as to have almost no color. Maybe it's because most of the added colors in Adobe RGB are in the cyan/green range, or maybe it's because there's twice as many green pixels in a Bayer array as there are red or blue, but green seems to frequently be the most affected color when rendering Adobe RGB files as if they were in sRGB colorspace. So for the winter photography I've been doing lately, all the pine trees come out looking faded and bland rather than popping out of the grey/white backgrounds. That's what led me to wonder about colorspace in the first place, and what made me realize that Pentax's JPG files come out looking terrible when the camera is set to Adobe RGB. Apparently there's more to it than that, though. Even many color-aware applications don't realize that these files are in Adobe RGB.

I'd still like to know if DCU4 produces the same results as the camera when it develops RAW files.

QuoteOriginally posted by distudio Quote
As far as I'm aware no versions of IE are colour managed at this point, I've no idea why, maybe it will eventually be available as a costly add on ;-)
Isn't IE costly enough as it is? (but now we're getting into a philosophical debate)

QuoteOriginally posted by distudio Quote
I think an AdobeRGB work-flow is quite workable so long as the user is aware of the steps that must be taken in order to make the files presentable for web or third party printing which generally translates to conversion to sRGB colour space.

On the personal print side of things shooting in AdobeRGB will generally end up producing better prints from a colour managed print application. Assuming of course that the user has at least gone to the trouble of obtaining and installing profiles for their preferred printer/paper combinations.

Shooting RAW provides the greatest flexibility as the colour space is not fixed but if this all appears too confusing/difficult/frustrating then sRGB is the easy way out. Simple really.
So I think we're all in agreement here:

a) leave the camera set to sRGB at all times for JPG pictures that are useful right out of the camera

b) use an external application to convert the RAW files if you want to work in a different colorspace (ie. Adobe RGB, ProPhoto, etc)

c) make sure the images you post on the web are in sRGB so they look the same to everyone in every browser

I still question the value of "working" in a wider colorspace when the ultimate result is sRGB anyways, but that's hard to prove or disprove without concrete evidence to show the benefits. I get the theory, it kinda sounds like working in higher resolution before scaling the image to its final size. I just don't see any results proving that this works the same way with colorspace.

Meanwhile, I'd love to know what the heck is up with Pentax's JPG files. Why do so many applications have trouble determining their proper colorspace? Thanks to distudio's help, I've been able to confirm that this is true of the K-7, the K-x, and the K20D. I'm still working this out on the Gimp mailing list, but they're kinda baffled by it too.
01-15-2010, 08:09 PM   #53
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There is only one way to ensure your photograph looks the same to all that view it, in terms of visuals:

Print it, frame it, light it absolutely evenly across all edges, and make sure that everyone that passes by can see the same color gamut (ie, isn't colorblind).

aRGB, sRGB, doesn't really matter that much. Most of the time sRGB just oversaturates colors in my experience. I am using a fully calibrated setup; my MacBook Pro, my printer, my external display, and my camera all use aRGB for all input and output (and all calibrated using the same Huey color calibrator). When I switch over to sRGB just to prove to myself I am right (how pompous of me to say, I don't mean it to sound like that), things look...inaccurate.

But then again, I am colorblind. But to my eyes, aRGB is a more accurate reproduction of the world.

I work mostly in B&W unless an image BEGS to be in color. In that case, I waste 10 sheets of paper to get that perfect print....just like in the darkroom. Nothing ever really changes.

01-15-2010, 09:52 PM   #54
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QuoteOriginally posted by GoremanX Quote
So I think we're all in agreement here:

a) leave the camera set to sRGB at all times for JPG pictures that are useful right out of the camera

b) use an external application to convert the RAW files if you want to work in a different colorspace (ie. Adobe RGB, ProPhoto, etc)

c) make sure the images you post on the web are in sRGB so they look the same to everyone in every browser
Pretty much, in my case I always shoot RAW+ and my JPEGs are set at 2MP (lets face it for the vast majority of prints 2MP is sufficient) sRGB

QuoteOriginally posted by GoremanX Quote
I still question the value of "working" in a wider colorspace when the ultimate result is sRGB anyways, but that's hard to prove or disprove without concrete evidence to show the benefits. I get the theory, it kinda sounds like working in higher resolution before scaling the image to its final size. I just don't see any results proving that this works the same way with colorspace.
I suppose you're not going to realise the proof until 1) you encounter an image where the extended gamut is significantly broader than sRGB and 2) where the resultant image is printed on a printer with a very wide gamut.

The application COULEUR.ORG will let you map the colour distribution/gamut of an image.

QuoteOriginally posted by GoremanX Quote
Meanwhile, I'd love to know what the heck is up with Pentax's JPG files. Why do so many applications have trouble determining their proper colorspace? Thanks to distudio's help, I've been able to confirm that this is true of the K-7, the K-x, and the K20D. I'm still working this out on the Gimp mailing list, but they're kinda baffled by it too.
I've no idea why this is, my ancient PS CS can determine the embedded colour space of my K20D and K-x images without any problem.
01-15-2010, 10:03 PM   #55
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QuoteOriginally posted by brofkand Quote
There is only one way to ensure your photograph looks the same to all that view it, in terms of visuals:

Print it, frame it, light it absolutely evenly across all edges, and make sure that everyone that passes by can see the same color gamut (ie, isn't colorblind).
Well yes, but color blindness is a whole other can of worms. By that logic, one could say that color management is a waste of time altogether since so many people perceive colors differently. The whole point of color management is to _render_ the colors consistently. So converting to sRGB for viewing on web browsers at least ensures that all web browsers will render the colors the same (that's the hope, anyways). Things like other people's monitor calibration or color blindness are beyond my ability to control.

QuoteOriginally posted by brofkand Quote
aRGB, sRGB, doesn't really matter that much. Most of the time sRGB just oversaturates colors in my experience.
I think this depends a lot of how the sRGB colorspace was achieved. If colors were just outright clipped, then the result can be noticeable. But if they're appropriately mapped to a close equivalent, the difference can be barely perceptible. Take the following for example (I seem to be generating a lot of "examples" lately, but I do these to see the results for myself more than anything else):

The left picture is the sRGB JPG version straight from the camera. The right picture is the Adobe RGB JPG picture from the camera, opened in Photoshop in Adobe RGB working space, and converted to sRGB using relative colorimetric intent with black point compensation and dithering enabled.



There's a very slight difference between the two, the file that was converted to sRGB is slightly more saturated, but you'd only notice it if the pictures were layered over each other and you flipped between the two. When I did the conversion, there was absolutely no perceptible difference on-screen. I did "undo" and "redo" a bunch of times while looking closely, and nothing changed at all. Is one more accurate than the other? I can't tell. Is one "better"? That's debatable.

The following were made using the camera's RAW file in Photoshop CS2. The left one was assigned sRGB right away. The right one was assigned Adobe RGB, then converted to sRGB afterwards using relative colorimetric intent with black point compensation and dithering enabled.



The two images are completely identical. There is no perceivable difference at all.

To me, all this proves is that the camera assigns colors differently than Photoshop does. Maybe the "intent" is different in the camera (absolute colorimetric, perceptual, etc.) Or maybe the color engines just give different results. But assuming that an Adobe RGB image converted to sRGB will become more saturated isn't necessarily true. In this particular case, it changed nothing at all.

(of course, this could also mean that my choice of subject just doesn't have any colors that require Adobe RGB to render).

Last edited by GoremanX; 01-15-2010 at 11:03 PM.
01-15-2010, 10:34 PM   #56
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QuoteOriginally posted by brofkand Quote
aRGB, sRGB, doesn't really matter that much. Most of the time sRGB just oversaturates colors in my experience. I am using a fully calibrated setup; my MacBook Pro, my printer, my external display, and my camera all use aRGB for all input and output (and all calibrated using the same Huey color calibrator). When I switch over to sRGB just to prove to myself I am right (how pompous of me to say, I don't mean it to sound like that), things look...inaccurate.
I would suggest that there's something not quite right with your setup if that's the case. The following image shows 4 renderings of my ProPhotoRGB image captured off my desktop (which is a wide gumut calibrated CRT). The top left is a ThumbsPlus windows, top right is Photoshop (sRGB proof), bottom left Internet Explorer, bottom right FireFox.

01-15-2010, 11:01 PM   #57
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QuoteOriginally posted by distudio Quote
Pretty much, in my case I always shoot RAW+ and my JPEGs are set at 2MP (lets face it for the vast majority of prints 2MP is sufficient) sRGB
That's interesting. I never really considered shooting at 2MP before. Again, the normal mentality is "bigger is better", which is so hard to get out of. But you're right, if I actually needed more than 2MP, I'd be doing PP on a RAW file anyways. All kinds of neat stuff to be learned in this thread

QuoteOriginally posted by distudio Quote
I suppose you're not going to realise the proof until 1) you encounter an image where the extended gamut is significantly broader than sRGB and 2) where the resultant image is printed on a printer with a very wide gamut.
Considering how dreary Winter looks, it's hard to find anything with much colour out here right now I certainly can't come up with anything indoors, even when I try real hard to setup a colorful studio scene to shoot on my bright orange pool table.

Does an IT8 color target have any colors out of sRGB gamut? I wouldn't think so, but if it does, I have a bunch of those...

QuoteOriginally posted by distudio Quote
The application COULEUR.ORG will let you map the colour distribution/gamut of an image.
Ack! No source code to compile!!! Bitter! I'll try running it with Wine tomorrow...

QuoteOriginally posted by distudio Quote
I've no idea why this is, my ancient PS CS can determine the embedded colour space of my K20D and K-x images without any problem.
Hah! I've got you beat on ancientness. I still have Photoshop 7 laying around. That's what I used for endless years until I inherited someone's CS2 recently. I just installed it to see how it would behave, and it DOES NOT properly detect the color profile of Pentax JPG files. It assumes sRGB, even when the profile is Adobe RGB. This is only true for Pentax camera JPG files as far as I can tell.
01-15-2010, 11:28 PM   #58
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QuoteOriginally posted by GoremanX Quote
That's interesting. I never really considered shooting at 2MP before. Again, the normal mentality is "bigger is better", which is so hard to get out of. But you're right, if I actually needed more than 2MP, I'd be doing PP on a RAW file anyways. All kinds of neat stuff to be learned in this thread
The plebs are being hoodwinked by the megapixel pushers. I don't know how many times I've put low res sample images on-line (at 1500px on the long side) with instructions that I'll make a print ready image of any one only to find that prints have been made from the samples with no complaints.

QuoteOriginally posted by GoremanX Quote
Does an IT8 color target have any colors out of sRGB gamut? I wouldn't think so, but if it does, I have a bunch of those...
Most commercial IT8 targets are regular wet prints so if what Bill suggested is true they most likely would be constrained within the sRGB colour gamut.

QuoteOriginally posted by GoremanX Quote
I just installed it to see how it would behave, and it DOES NOT properly detect the color profile of Pentax JPG files. It assumes sRGB, even when the profile is Adobe RGB. This is only true for Pentax camera JPG files as far as I can tell.
I wonder if this problem has anything to do with the CMS capabilities/settings of the particular OS?
01-16-2010, 12:06 AM   #59
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QuoteOriginally posted by distudio Quote
I wonder if this problem has anything to do with the CMS capabilities/settings of the particular OS?
That was my initial thought, but I have Photoshops 7.0 and CS2 installed side-by-side in the exact same environment, and they react differently when opening up Pentax JPG files that have an Adobe RGB profile embedded. My guess is Adobe "learned" how to deal with Pentax files and incorporated this change into the CS (8.0) release. After all, Photoshop 7.0 was released in August 2002 and Photoshop CS came out in October 2003. The first Pentax DSLR (*ist D) came out exactly between those two Photoshop releases. I'm sure that's no coincidence (as far as file format support in Photoshop CS).

What exactly is the point of generating non-standard JPG files? It's rather annoying.

I finally made the effort to start up a virtualized Windows XP and installed DCU4 so I could check its output. When converting a RAW file to JPG with Adobe RGB color profile, DCU4 does not generate what I'm starting to think of as "defective" JPG files. DCU4 embeds the profile in a standard way that is detected by Gimp, Photoshop 7 and everything else. Apparently these "defective" JPG files are exclusive to Pentax cameras.

On a side note, I find DCU4 horrible to use. I no longer regret the fact that it doesn't work natively on my platform. It might be because my virtualized Windows XP is in French, so DCU4 installed itself in French, and I have no clue what the French photography technical terms are. Or... it might be because DCU4 is really crap.
01-16-2010, 12:25 AM   #60
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This whole subject is weighing on my mind I just went to bed and had another thought while trying to sleep. If the Adobe RGB JPG files from the camera have the color profile embedded in a non-standard way, do the sRGB JPG files have the same issue? So far, I've only been working in sRGB anyways, so I assumed the sRGB JPG files were fine since they opened in sRGB.

So I set Gimp to Adobe RGB working space, and I opened a camera-generated JPG that's in sRGB colorspace. The color profile was NOT detected properly! Gimp assumed it was in Adobe RGB colorspace. The picture ended up looking super-saturated as a result.

So ALL Pentax camera-generated JPG files have the color profile embedded in some bizarre non-standard way.

dstudio: I have a feeling you're seeing my out-of-camera sRGB files as over-saturated since you have a wide-gamut monitor and Firefox is set to display in Adobe RGB. The screenshots you showed earlier tend to support that. That would mean that your carefully-controlled color managed system is in fact being defeated by Pentax's "defective" JPG files.

(I hope I'm not jumping the gun by calling them "defective", but it's so easy to label things negatively)
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